Purification and characterization of a platelet aggregation inhibitor acidic phospholipase A2 from Indian saw-scaled viper (Echis carinatus) venom

An acidic phospholipase A(2) (EC-I-PLA(2)) has been purified from the Indian saw-scaled viper (Echis carinatus) venom through a combination of column chromatography and electrophoresis. EC-I-PLA(2) has a molecular weight of 16000 by SDS-PAGE. It was focussed between pH 4.2 and 4.8 by isoelectro focussing. EC-I-PLA(2) was non-lethal to mice and devoid of neurotoxicity, myotoxicity, anticoagulant activity and cytotoxicity. It induced mild oedema in the foot pads of mice. The purified PLA(2) inhibited ADP, collagen and epinephrine induced human platelet aggregation and the inhibition was both dose and time dependent. (C) 1999 Elsevier Science Ltd. All rights reserved

PAF-acether in AK-5 tumour cells

PAF-Acether fraction derived from stimulated AK-5 tumour cells, aggregated human platelets. The platelet aggregating ability increased linearly with increasing concentration of the stimulant, calcium ionophore A23187, and reached a maximum at 6 microM in 25 minutes. This factor had biological and chemical properties identical to authentic PAF-acether. Our results demonstrate that, although PAF-acether is produced mainly from pro-inflammatory cells, it appears to be produced even in tumour cells